/*
 *     Android基础开发个人积累、沉淀、封装、整理共通
 *     Copyright (c) 2016. 曾繁添 <zftlive@163.com>
 *     Github：https://github.com/zengfantian || http://git.oschina.net/zftlive
 *
 *     Licensed under the Apache License, Version 2.0 (the "License");
 *     you may not use this file except in compliance with the License.
 *     You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 *     Unless required by applicable law or agreed to in writing, software
 *     distributed under the License is distributed on an "AS IS" BASIS,
 *     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *     See the License for the specific language governing permissions and
 *     limitations under the License.
 */

package com.zftlive.android.library.widget.container;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.List;

/**
 * 流式布局容器
 *
 * @author 曾繁添
 * @version 1.0
 */
public class FlowLayout extends ViewGroup {

    /**
     * 存储所有的View，按行记录
     */
    private List<List<View>> mAllViews = new ArrayList<List<View>>();

    /**
     * 记录每一行的最大高度
     */
    private List<Integer> mLineHeight = new ArrayList<Integer>();

    /**
     * 日志输出TAG
     */
    private static final String TAG = "FlowLayout";

    /**
     * 限制最大行数
     */
    private int mMaxLineNum = -1;

    public FlowLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public FlowLayout(Context context) {
        super(context);
    }

    public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public void setMaxLine(int lineNumMax) {
        mMaxLineNum = lineNumMax;
    }

    /**
     * 负责设置子控件的测量模式和大小 根据所有子控件设置自己的宽和高
     */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        // 获得它的父容器为它设置的测量模式和大小
        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
        int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
        int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

        Log.e(TAG, sizeWidth + "," + sizeHeight);

        // 如果是warp_content情况下，记录宽和高
        int width = 0;
        int height = 0;

        //记录每一行的宽度，width不断取最大宽度
        int lineWidth = 0;

        //每一行的高度，累加至height
        int lineHeight = 0;
        int cCount = getChildCount();
        int lineNum = 0;

        // 遍历每个子元素
        for (int i = 0; i < cCount; i++) {
            View child = getChildAt(i);
            // 测量每一个child的宽和高
            measureChild(child, widthMeasureSpec, heightMeasureSpec);
            // 得到child的lp
            MarginLayoutParams lp = (MarginLayoutParams) child
                    .getLayoutParams();
            // 当前子空间实际占据的宽度
            int childWidth = child.getMeasuredWidth() + lp.leftMargin
                    + lp.rightMargin;
            // 当前子空间实际占据的高度
            int childHeight = child.getMeasuredHeight() + lp.topMargin
                    + lp.bottomMargin;
            //如果加入当前child，则超出最大宽度，则的到目前最大宽度给width，类加height 然后开启新行
            if (lineWidth + childWidth > sizeWidth) {
                width = Math.max(lineWidth, childWidth);// 取最大的
                lineWidth = childWidth; // 重新开启新行，开始记录
                // 叠加当前高度，
                height += lineHeight;
                // 开启记录下一行的高度
                lineHeight = childHeight;

                // 限制行数
                lineNum++;
                if (mMaxLineNum != -1 && lineNum >= mMaxLineNum) {
                    break;
                }
            } else
            // 否则累加值lineWidth,lineHeight取最大高度
            {
                lineWidth += childWidth;
                lineHeight = Math.max(lineHeight, childHeight);
            }
            // 如果是最后一个，则将当前记录的最大宽度和当前lineWidth做比较
            if (i == cCount - 1) {
                width = Math.max(width, lineWidth);
                height += lineHeight;
            }
        }
        setMeasuredDimension((modeWidth == MeasureSpec.EXACTLY) ? sizeWidth
                : width, (modeHeight == MeasureSpec.EXACTLY) ? sizeHeight
                : height);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        mAllViews.clear();
        mLineHeight.clear();

        int lineNum = 0;

        int width = getWidth();
        int lineWidth = 0;
        int lineHeight = 0;
        // 存储每一行所有的childView
        List<View> lineViews = new ArrayList<View>();
        int cCount = getChildCount();
        // 遍历所有的孩子
        for (int i = 0; i < cCount; i++) {
            View child = getChildAt(i);
            MarginLayoutParams lp = (MarginLayoutParams) child
                    .getLayoutParams();
            int childWidth = child.getMeasuredWidth();
            int childHeight = child.getMeasuredHeight();

            // 如果已经需要换行
            if (childWidth + lp.leftMargin + lp.rightMargin + lineWidth > width) {
                // 记录这一行所有的View以及最大高度
                mLineHeight.add(lineHeight);
                // 将当前行的childView保存，然后开启新的ArrayList保存下一行的childView
                mAllViews.add(lineViews);
                lineWidth = 0;// 重置行宽
                lineViews = new ArrayList<View>();

                //限制行数
                lineNum++;
                if (mMaxLineNum != -1 && lineNum >= mMaxLineNum) {
                    break;
                }
            }
            //如果不需要换行，则累加
            lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
            lineHeight = Math.max(lineHeight, childHeight + lp.topMargin
                    + lp.bottomMargin);
            lineViews.add(child);
        }
        // 记录最后一行
        mLineHeight.add(lineHeight);
        mAllViews.add(lineViews);

        int left = 0;
        int top = 0;
        // 得到总行数
        int lineNums = mAllViews.size();
        for (int i = 0; i < lineNums; i++) {
            // 每一行的所有的views
            lineViews = mAllViews.get(i);
            // 当前行的最大高度
            lineHeight = mLineHeight.get(i);
            // 遍历当前行所有的View
            for (int j = 0; j < lineViews.size(); j++) {
                View child = lineViews.get(j);
                if (child.getVisibility() == View.GONE) {
                    continue;
                }
                MarginLayoutParams lp = (MarginLayoutParams) child
                        .getLayoutParams();
                // 计算childView的left,top,right,bottom
                int lc = left + lp.leftMargin;
                int tc = top + lp.topMargin;
                int rc = lc + child.getMeasuredWidth();
                int bc = tc + child.getMeasuredHeight();
                child.layout(lc, tc, rc, bc);
                left += child.getMeasuredWidth() + lp.rightMargin
                        + lp.leftMargin;
            }
            left = 0;
            top += lineHeight;
        }
    }

    @Override
    protected LayoutParams generateLayoutParams(LayoutParams p) {
        return new MarginLayoutParams(p);
    }

    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new MarginLayoutParams(getContext(), attrs);
    }

    @Override
    protected LayoutParams generateDefaultLayoutParams() {
        return new MarginLayoutParams(LayoutParams.MATCH_PARENT,
                LayoutParams.MATCH_PARENT);
    }
}
